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From |
"Lachenbruch, Peter" <Peter.Lachenbruch@oregonstate.edu> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
st: RE: Detection of disease |

Date |
Thu, 14 Aug 2008 08:57:08 -0700 |

I have my own spreadsheet I've used for many years and the sample size calculation give n=16. However, my question is a little different: do you really want to test the alternative that p=0? This seems unrealistic in the real world. PASS will not accept p=0 as an alternative. If I use p=0.00001, it gives n=14. I would worry about the freeware a bit. Tony Peter A. Lachenbruch Department of Public Health Oregon State University Corvallis, OR 97330 Phone: 541-737-3832 FAX: 541-737-4001 -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Carlo Georges Sent: Thursday, August 14, 2008 2:54 AM To: statalist@hsphsun2.harvard.edu Subject: st: Detection of disease I tried to reproduce in stata the calculation needed for the following case: I need to determine the sample size, required to detct the presence of disease in a population. The formula is rather complex so it is difficult to paste in here, For example i need to detect with 95% confidence the abscence of disease in a population where the presumed prevalence would be 20%. How lrge a sample size do I need to be 95% certain that the population is free from disease. I used a program "Winepiscope" freeware, that calculated a samplesize of 14. in stata i tried : sampsi 0.2 0, power(0.9) onesample and I get a result of :16 Can stata handle this type of calculation? * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: RE: Detection of disease***From:*Ronan Conroy <rconroy@rcsi.ie>

**References**:**Re: st: No (basic) graphs in Stata 10.1***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**st: Detection of disease***From:*"Carlo Georges" <georgesc@pt.lu>

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